'\" t
.\"     Title: zmq_ctx_set
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/>
.\"      Date: 03/10/2014
.\"    Manual: 0MQ Manual
.\"    Source: 0MQ 4.0.1
.\"  Language: English
.\"
.TH "ZMQ_CTX_SET" "3" "03/10/2014" "0MQ 4\&.0\&.1" "0MQ Manual"
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.SH "NAME"
zmq_ctx_set \- set context options
.SH "SYNOPSIS"
.sp
\fBint zmq_ctx_set (void \fR\fB\fI*context\fR\fR\fB, int \fR\fB\fIoption_name\fR\fR\fB, int \fR\fB\fIoption_value\fR\fR\fB);\fR
.SH "DESCRIPTION"
.sp
The \fIzmq_ctx_set()\fR function shall set the option specified by the \fIoption_name\fR argument to the value of the \fIoption_value\fR argument\&.
.sp
The \fIzmq_ctx_set()\fR function accepts the following options:
.SS "ZMQ_IO_THREADS: Set number of I/O threads"
.sp
The \fIZMQ_IO_THREADS\fR argument specifies the size of the 0MQ thread pool to handle I/O operations\&. If your application is using only the \fIinproc\fR transport for messaging you may set this to zero, otherwise set it to at least one\&. This option only applies before creating any sockets on the context\&.
.TS
tab(:);
lt lt.
T{
.sp
Default value
T}:T{
.sp
1
T}
.TE
.sp 1
.SS "ZMQ_MAX_SOCKETS: Set maximum number of sockets"
.sp
The \fIZMQ_MAX_SOCKETS\fR argument sets the maximum number of sockets allowed on the context\&.
.TS
tab(:);
lt lt.
T{
.sp
Default value
T}:T{
.sp
1024
T}
.TE
.sp 1
.SS "ZMQ_IPV6: Set IPv6 option"
.sp
The \fIZMQ_IPV6\fR argument sets the IPv6 value for all sockets created in the context from this point onwards\&. A value of 1 means IPv6 is enabled, while 0 means the socket will use only IPv4\&. When IPv6 is enabled, a socket will connect to, or accept connections from, both IPv4 and IPv6 hosts\&.
.TS
tab(:);
lt lt.
T{
.sp
Default value
T}:T{
.sp
0
T}
.TE
.sp 1
.SH "RETURN VALUE"
.sp
The \fIzmq_ctx_set()\fR function returns zero if successful\&. Otherwise it returns \-1 and sets \fIerrno\fR to one of the values defined below\&.
.SH "ERRORS"
.PP
\fBEINVAL\fR
.RS 4
The requested option
\fIoption_name\fR
is unknown\&.
.RE
.SH "EXAMPLE"
.PP
\fBSetting a limit on the number of sockets\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
void *context = zmq_ctx_new ();
zmq_ctx_set (context, ZMQ_MAX_SOCKETS, 256);
int max_sockets = zmq_ctx_get (context, ZMQ_MAX_SOCKETS);
assert (max_sockets == 256);
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.sp
\fBzmq_ctx_get\fR(3) \fBzmq\fR(7)
.SH "AUTHORS"
.sp
This page was written by the 0MQ community\&. To make a change please read the 0MQ Contribution Policy at \m[blue]\fBhttp://www\&.zeromq\&.org/docs:contributing\fR\m[]\&.
